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I'm a bit confused by how gcc encodes relative jumps. I have the following:

int main(void)
    __asm__ __volatile__(
        "jmp label\n"
        "label:\n"
        "nop\n"
    return 0;
Building this (gcc -c -o test.o test.c) shows the following (objdump -M intel -d test.o):
0000000000000000 <main>:
   0:   55                      push   rbp
   1:   48 89 e5                mov    rbp,rsp
   4:   eb 00                   jmp    6 <label>
0000000000000006 <label>:
   6:   90                      nop
rasm2 -d eb00 shows jmp 2, which means the jump is being performed with an offset of 2. Now, I had understood that relative jumps' offsets are added to the current value of eip, which should be pointing at the next instruction (i.e. nop). This encoding makes me think that the offset is relative to the address of the jmp itself. Shouldn't the jmp be encoded as jmp 0, since nop is already at label?
                If that's true, that's extremely confusing. I'm surprised that even radare would display the offset as 2.
– Martin
                Feb 17, 2019 at 5:20
                @Martin wouldn't it be more confusing if radare decided to do it different from all the other tools?
– harold
                Feb 17, 2019 at 5:24
                I don't know. Maybe radare should include an option to show the real offsets. In any case, this seems to clear things up for me. Thanks, harold
– Martin
                Feb 17, 2019 at 5:34
                @martin Normally disassemblers display the absolute address of the destination for the operand of jump instructions. I would've expected rasm2 to display jmp 6 just like objdump did.  It's possible that rasm2 thinks that the JMP instruction is at address 0 for whatever reason.
– Ross Ridge
                Feb 17, 2019 at 5:58
                @MikkoRantalainen the compiler had no choice in this case because inline asm was used to create that useless jump
– harold
                Feb 26, 2022 at 10:38
        
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